Vacuum pump

Abstract

The invention relates to a heat insulation structure having the function of retaining a high temperature in a vacuum exhaust chamber in a rotary type vacuum pump and the function of cooling bearings at the same time, and particularly has for its object the provision of a structure for preventing bearings or shaft seals from becoming so high in temperature as to be damaged when a high temperature is to be retained in an exhaust chamber with respect to a vacuum pump for exhausting reactive gases as in a semiconductor process. As a means to achieve the object, in a vacuum pump comprising an introduction device having a vacuum exhaust chamber and adapted to introduce a process gas into the vacuum exhaust chamber, an exhaust device for exhausting the process gas out of the vacuum exhaust chamber, a housing for separating the vacuum exhaust chamber from outside, with a rotor installed fro rotation in the housing through a bearing, a heat insulation device is provided between the vacuum exhaust chamber and the bearing. Further, a metal whose thermal conductivity is higher than that of the material of the housing is incorporated as a heat transmission device into the housing.

1 . A vacuum pump comprising: 
 an introducing device having a vacuum exhaust chamber for introducing a process gas into the vacuum exhaust chamber;    an exhausting device for exhausting the process gas to outside of the vacuum exhaust chamber;    a housing partitioning the vacuum exhaust chamber and outside; and    a rotor rotatably fixed to inside of the housing via a bearing,    wherein an insulating device is provided between the vacuum exhaust chamber and the bearing.    
   
   
       2 . The vacuum pump according to  claim 1 , wherein a material having a heat conductivity lower than a heat conductivity of a material of the housing is used as the insulating device.  
   
   
       3 . The vacuum pump according to  claim 1 , wherein a resin having a heat conductivity lower than a heat conductivity of the housing and having a high corrosion resistance is used as the insulating device.  
   
   
       4 . The vacuum pump according to  claim 1 , characterized in that a hollow insulating member is used as the insulating device.  
   
   
       5 . The vacuum pump according to  claim 1 , wherein the housing is constituted by a bearing case provided with the bearing and a main casing at a surrounding of the rotor and a supporting member of the insulating device is provided between the bearing case and the main housing.  
   
   
       6 . The vacuum pump according to  claim 1 , wherein a heat conducting device having a heat conductivity higher than a heat conductivity of a material of the insulating device is provided between the insulating device and the vacuum exhaust chamber.  
   
   
       7 . The vacuum pump according to  claim 1 , wherein a second insulating device is provided on a side of an atmosphere of an outer periphery of the housing.  
   
   
       8 . The vacuum pump according to  claim 1 , wherein a heat conducting device is provided at the housing or/and an outer periphery of the housing.  
   
   
       9 . The vacuum pump according to  claim 8 , wherein a heat pipe is used as the heat conducting device.  
   
   
       10 . The vacuum pump according to  claim 8 , characterized in that a metal having a heat conductivity more excellent than the heat conductivity of the material of the housing is used as the heat conducting device.  
   
   
       11 . A vacuum pump characterized in a vacuum pump including introducing device having a vacuum exhaust chamber for introducing a process gas into the vacuum exhaust chamber, exhausting device for exhausting the process gas to outside of the vacuum exhaust chamber, and a housing partitioning the vacuum exhaust chamber and outside, wherein a rotor is rotatably fixed to inside of the housing via a bearing, and wherein heat conducting device is provided at an outer periphery of the housing or/and an outer periphery of the housing.  
   
   
       12 . The vacuum pump according to  claim 11 , characterized in that a metal having a heat conductivity more excellent than a heat conductivity of a material of the housing is used as the heat conducting device.  
   
   
       13 . The rotary vacuum pump according to  claim 3 , characterized in that an insulating means made of the resin having a heat conductivity lower that of a material of the housing and having a corrosion resistance is disposed at a position on which the vacuum exhaust chamber directly contacts.  
   
   
       14 . The rotary vacuum pump according to  claim 9 , characterized in that the heating conducting means is disposed between the introducing means and the exhausting means so as to equalize heating states between a vicinity of the introducing means and a vicinity of the exhausting means.  
   
   
       15 . The rotary vacuum pump according to claims  1 , characterized in that the insulating means is disposed between the vacuum exhaust chamber and the bearing both on a side of the introducing means and a side of the exhausting means.